U.S. Ends Its Military Mission After More Than Two Decades

The last American troops have left Iraq, closing the latest chapter of a military presence that began with the U.S.-led invasion of 2003, formally ended once before in 2011, and resumed three years later when the Islamic State swept across large parts of Iraq and Syria.

U.S. Central Command announced that American forces and equipment completed their departure from Erbil Air Base in Iraqi Kurdistan on September 30, bringing the Iraq-based mission of Operation Inherent Resolve to an end. The command headquarters responsible for the operation has been transferred to Jordan, from where the United States and its partners intend to continue operations against Islamic State militants in Syria.

The withdrawal completes a two-stage agreement negotiated by Baghdad and Washington under President Joe Biden in 2024 and implemented through the administration of President Donald Trump. Under that arrangement, the formal military mission of the U.S.-led international coalition inside Iraq was to conclude by September 2025, while Iraq continued to host forces supporting counter-ISIS operations in neighboring Syria until September 2026.

That distinction explains why American troops remained at Erbil after much of the coalition infrastructure elsewhere in Iraq had already disappeared. U.S. forces left Al Asad Air Base in western Anbar province and consolidated their remaining personnel around Erbil as the drawdown proceeded. The September 30 departure therefore represents the completion of the second and final phase of the process.

For Iraq, the withdrawal carries powerful historical symbolism. American forces invaded the country in March 2003 and overthrew Saddam Hussein’s government within weeks, but the occupation that followed produced years of insurgency and sectarian warfare. More than 4,500 American service members died in Iraq before the United States withdrew its combat forces in December 2011.

But the departure proved temporary. In 2014, Islamic State captured Mosul and large areas of northern and western Iraq, prompting Baghdad to request international military assistance. Washington returned at the head of an international coalition, providing air power, intelligence, advisers and logistical support as Iraqi forces, Kurdish Peshmerga and other armed formations gradually retook the territory. By the end of 2017, Baghdad had declared the group’s territorial rule defeated.

The mission subsequently shifted from large-scale combat toward advising, intelligence sharing and support for Iraqi counterterrorism forces. By 2024, roughly 2,500 American troops remained in Iraq, alongside about 900 in Syria, as Washington and Baghdad began negotiating how to replace the coalition structure with a more conventional bilateral security relationship.

The withdrawal, however, comes at a delicate moment. Islamic State no longer controls cities or significant territory in Iraq, but Iraqi and Kurdish security officials say the organization retains networks of sleeper cells capable of operating in remote areas and exploiting gaps between security forces. Kurdish commander Sirwan Barzani told Reuters that movement by suspected ISIS cells had increased in the weeks preceding the American departure. Iraqi officials also said security forces had uncovered a suspected cell preparing suicide attacks around the time of the withdrawal.

The principal concern is less a sudden return of the Islamic State’s former “caliphate” than the gradual rebuilding of an insurgent network. American surveillance aircraft, drones, intelligence capabilities and logistical systems provided Iraqi forces with tools that can be difficult to replace quickly. Iraqi authorities, meanwhile, argue that their armed forces have developed sufficiently over the past decade to assume full responsibility for domestic security.

A second consequence concerns Iran. Iranian officials and Tehran-aligned Iraqi armed groups have publicly celebrated the American departure, describing it as a victory for Iraqi sovereignty and for the so-called “axis of resistance.” Iran has built extensive political, economic and security relationships inside Iraq since the overthrow of Saddam Hussein, while several powerful Iraqi armed groups maintain close relationships with Tehran.

Some Iraqi analysts fear that removing the American military presence could strengthen those factions’ influence over security and political decision-making. Supporters of the withdrawal make the opposite argument: that the absence of foreign troops removes one of the main justifications used by armed factions for maintaining forces outside ordinary state structures.

Baghdad has consequently linked the withdrawal to a broader effort to establish state control over weapons. Iraqi officials have said the post-coalition relationship with Washington should increasingly revolve around bilateral defense cooperation, training, intelligence, arms procurement and economic ties rather than foreign forces permanently stationed on Iraqi soil. A joint Iraqi-American technical committee has been tasked with defining that new security relationship.

Washington is also not abandoning the wider counter-ISIS campaign. Operation Inherent Resolve will continue from its new headquarters in Jordan, focusing principally on Syria, where Islamic State networks remain active.

For the first time since the Islamic State crisis of 2014, Iraq will attempt to manage its internal security without American troops stationed inside the country. Whether the departure ultimately strengthens Iraqi sovereignty, expands the room available to Iran-aligned factions, or creates opportunities for Islamic State remnants will depend largely on the ability of Baghdad’s institutions to fill the military and political space Washington has left behind.